ISO 15208 pdf download Continuous hot-dip zinc-coated twin- roll cast steel sheet of commercial quality
This product is normally suitable for welding, if appropriate welding methods and procedure are used,with special attention to the heavier coatings.
Continuous hot-dip zinc-coated steel sheet is a suitable base for paint but the first treatment may bedifferent from those used on uncoated steel. Pre-treatment primers,chemical conversion coatings(chromate, phosphate or oxide type) and some paints specially formulated for direct application to zincsurfaces are all appropriate first treatments for hot-dip zinc-coated sheet. In drawing up a paintingschedule, consideration shall be given to whether the hot-dip zinc-coated sheet shall be ordered in thepassivated or not passivated state.
NOTE Surfaces with certain passivation treatments (e.g.chromated) are not suitable for phosphating or theapplication of a pre-treatment (etch) primer.
5.8 Surface treatment
5.8.1 Mill passivation
A chemical treatment is normally applied to zinc coatings to minimize the hazard of wet storage stain(white rust) during shipment and storage.However, the inhibiting characteristics of the treatment arelimited, and if a shipment is received wet, the material shall be used immediately or dried.
Zinc-coated twin-roll cast steel sheet may be processed chemically at the manufacturer’s works toprepare all types of coatings for painting without further treatment, except normal cleaning.
When specified, the zinc-coated twin-roll cast steel sheet as produced shall be oiled to prevent marringand scratching of the soft surface during handling or shipping and to minimize wet storage stain.
NOTE When the zinc-coated twin-roll cast steel sheet has received a passivating treatment, oiling furtherminimizes the hazard of wet storage stain.
5.9Coated coil joining
Continuous coil coating lines use various methods to join coil ends. These methods include lap welding.butt welding and stitching.The shipment of coils containing the joined ends is permitted, if agreed uponbetween the purchaser and manufacturer.
5.10 Dimensional and shape tolerances
5.10.1 Dimensional and shape tolerances applicable to zinc-coated twin-roll cast steel sheet shall be asgiven in IS0 16163.The tolerances for thickness apply to products whose thickness is a combination ofbase-metal and coating thickness.
5.10.2 When the base-metal thickness is specified, the thickness tolerances of lS0 16163 shall apply tothe product thickness, as calculated in accordance with Annex A.
When required, one representative transverse sample from each lot of 50 t or less for shipment shallbe taken for the tensile test to verify conformance with the requirements of 5.4.Transverse test piecesshall be taken mid-way between the centre and the edge of the sheet as-rolled.
6.2.1 Coating mass
126.96.36.199 The producer/manufacturer shall develop a testing plan with a frequency sufficient toadequately characterize the lot of material and ensure conformance with specification requirements.
188.8.131.52The purchaser may conduct verification tests by securing a sample piece of approximately300 mm in length by the as-coated width and cutting three test specimens, one from the mid-widthposition and one from each side not closer than 25 mm from the side edge.The minimum area of eachspecimen shall be 1 200 mm2.
The triple-spot test result shall be the average coating mass found on the three specimens taken inaccordance with 6.2.1.
The single-spot test result shall be the minimum coating mass found on any one of the three specimensused for the triple-spot test.Material, which has been slit from wide coil, shall be subjected to a single-spot test only.